This invention relates to tools for performing downhole functions in horizontal or highly deviated wells, and to rotating one or more downhole tools to desired orientations before performing the associated functions.
In a product recovery well, such as in the oil and gas industry, several downhole functions must be performed with tools lowered through the well pipe or casing. These tools may include, depending on the required tasks to be performed, perforating guns to produce holes in the well pipe wall to access a target formation, well-sealing tools, sensors and valves.
Many wells are drilled at an angle to vertical, or have a vertical upper portion and a lower portion that deviates substantially from vertical. Depending upon the angle of inclination of the well, such wells are referred to as horizontal or highly deviated wells. The tools used in these wells are often tubing-conveyed, i.e. lowered into the well bore on the end of multiple sections of tubing or a long metal tube from a coil, and activated by pressurizing the interior of the tubing.
Due to properties of some geologic formations and well casing structural considerations, better methods of controlling the accurate positioning of downhole tools are desirable. A horizontal well perforated on the lower side of the casing, for instance, can be less likely to become plugged with flowing sand, or to cause the collapse of the adjacent formation, than one perforated on its upper side.